package com.hmdp.utils;

import cn.hutool.core.lang.UUID;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;

import java.util.Collections;
import java.util.concurrent.TimeUnit;

public class SimpleRedisLock implements ILock {
    private String name;
    private StringRedisTemplate stringRedisTemplate;

    public SimpleRedisLock(String name, StringRedisTemplate redisTemplate) {
        this.name = name;
        this.stringRedisTemplate = redisTemplate;
    }

    private static final String KEY_PREFIX = "lock:";
    private static final String ID_PREFIX = UUID.randomUUID().toString(true)+"-";
    private static final DefaultRedisScript<Long> UNLOCK_SCRIPT;
    static {
        UNLOCK_SCRIPT = new DefaultRedisScript<>();
        UNLOCK_SCRIPT.setLocation(new ClassPathResource("unlock.lua"));
        UNLOCK_SCRIPT.setResultType(Long.class);
    }
    /**
     * 获取锁
     * @param timeoutSec 锁持有的超时时间，过期后自动释放
     * @return
     */
    @Override
    public boolean tryLock(long timeoutSec) {
        //获得当前线程标识，用uuid+线程id
        String threadId = ID_PREFIX+Thread.currentThread().getId();

        Boolean success = stringRedisTemplate.opsForValue().setIfAbsent(KEY_PREFIX + name, threadId, timeoutSec, TimeUnit.SECONDS);

        return Boolean.TRUE.equals(success);
    }

    /**
     * 释放锁
     */
    @Override
    public void unlock() {
       //调用lua脚本
        stringRedisTemplate.execute(
                UNLOCK_SCRIPT,
                Collections.singletonList(KEY_PREFIX+name),
                ID_PREFIX+Thread.currentThread().getId()
        );


    }
   /* @Override
    public void unlock() {
        //获取当前线程的标识
        String threadId = ID_PREFIX+Thread.currentThread().getId();
        //获取锁中的标识
        String id = stringRedisTemplate.opsForValue().get(KEY_PREFIX +name);
        //如果相同，才可以释放锁
        if(threadId.equals(id)) {
            stringRedisTemplate.delete(KEY_PREFIX + name);
        }



    }*/
}
